Athlete’s heart or hypertrophic cardiomyopathy?

Abstract

Intensive endurance training is able to cause a distinct pattern of functional and structural changes of the cardiovascular system. In an unknown proportion of athletes a so called "athlete's heart" develops. There is an overlap between this type of physiologic cardiac hypertrophy and mild forms of hypertrophic cardiomyopathy (HCM), the most common genetic disorder of the cardiovascular system with a prevalence of 0.2%. HCM is caused by mutations in 14 genes coding for sarcomere proteins. In the literature up to 50% of cases of sudden cardiac death (SCD) in younger sportsmen were connected to hypertrophic cardiomyopathy. It is therefore the most common cause of SCD in highly trained young athletes. Because of this data a great interest in distinguishing these two diagnoses exists. Apart from clinical examination and some non-specific ECG-changes, Echocardiography is the method of choice. The athlete's heart shows an eccentric biventricular hypertrophy with wall thicknesses under 15 mm and a moderately dilated left ventricle (LVEDD up to 58 mm). HCM is commonly characterized by asymmetric left ventricular hypertrophy with a reduced LV-diameter. In up to 70% of cases left ventricular outflow tract obstruction is evident during stress echocardiography. Systolic function is normal in highly trained athletes and the majority of HCM patients as well. There are important differences regarding diastolic filling patterns. Physiological hypertrophy is consistent with a normal diastolic function with even increased early diastolic filling. In case of HCM diastolic dysfunction (mostly relaxation disturbances) occurs in the majority of patients and is therefore inconsistent with an athlete's heart. If the diagnosis could not be stated using echocardiography, methods like cardiac-MRI, metabolic exercise testing, histological studies of endomyocardial biopsies and genetic testing can provide further information. A correct diagnosis may on the one hand prevent some athletes from sudden cardiac death. On the other hand sportsmen with an athlete's heart are reassured and able to continue as competitors. New insights into electrophysiological changes during physiological hypertrophy could probably change this view.

Assessment of Mechanical Cardiac Function in Elite Athletes

“…2a). Previous research has shown that individuals diagnosed with HCM demonstrated diastolic dysfunction [5,21], and it is suggested that this can be differentiated from those individuals that have physiological hypertrophy resulting from exercise training [21,44,51,52]. In Fig.…”

“…The Echo data support the BCG observations. Lauschke and co-workers have suggested that changes in diastolic function maybe important to help clarify differences between the "athletic" and "pathological" heart [54], and thus warrants further investigation. This study advances our understanding of HCM, but more detailed studies comparing Echo, cardiac MRI and BCG are required to confirm the sensitivity and specificity of the BCG in detecting cardiac anomalies.…”

“…With Echo, pathological HCM is characterized by left and right chamber alterations including LV septal anomaly, posterior wall thickness, impaired ventricular diastolic filing, increased ventricular stiffness and mitral valve systolic anterior motion (SAM). Cardiac MRI is likewise useful to localize and quantify cardiac hypertrophy, as it is capable of measuring both ventricles to detect biventricular hypertrophy [21][22][23]. All of these methods have their distinct advantages, and when combined, provide the clinician with a thorough and reliable methodology for diagnosing HCM [24].…”

Left Ventricular Wall Thickness and the Presence of Asymmetric Hypertrophy in Healthy Young Army Recruits

“…Currently, physiological and pathological forms of hypertrophy are differentiated using a variety of diagnostic algorithms and echocardiography. 2,3 However, uncertainty frequently persists and physicians are frequently turning to cardiovascular magnetic resonance (CMR) to resolve such cases. This technique offers superior spatial resolution, better visualization of the lateral wall, and apex and is unlimited by echocardiographic windows; however, a normal range for wall thickness measurements is lacking and the echo cutoff of 13 mm is frequently used.…”

Evaluation of Left Atrial Function in Physiological and Pathological Left Ventricular Myocardial Hypertrophy by Real‐time Tri‐plane Strain Rate Imaging

“…4 With the development of modern UCG and other imaging examining methods, these changes were further revealed and confirmed. In 1975, Morganroth 5 and fellow researchers first found evidence of a thickened LV wall, increased weight, and end-diastolic volume of the left ventricle in athletes by UCG.…”